Multiphase reactors are widely used in various industry sectors such as metallurgy, chemical engineering, petrochemical engineering, and environmental protection. Owing to the particularity of different application fields, the reactor components that speed up reactions among gas-liquid-solid three-phase or gas-liquid, gas-solid, liquid-solid two-phase should have their own characteristics, according to practical requirements. For instance, the Chinese patent No. ZL98113470.x, entitled “A Multiphase Jet Osmotic Dissolution reactor”, discloses a reactor including a spherical perforated focused injector, a draft tube, an expanding vessel and an osmotic cavity. Its characteristics are that the small conical orifices on the surface of the spherical body of the spherical perforated focused injector are connected to transferring conduits of the multiphase-fluid, respectively; the expanding vessel consists of a cone-shaped cavity and an expanding cone, with clearance between them; there are cylindrical orifices with convex helical bore line on the top end of the small conical orifices of the spherical body, and there is a short inward convex helical bore line on the inner wall of the draft tube terminal. Aiming at improving the osmotic effect of at least two-phase fluids, this prior art invention is made with its own characteristics of a build-in member. The inventor of the present application had presented a set of new technical solutions in the process of solving pollution problems of sulfur dioxide-containing flue gas which was discharged during metallurgical processes, achieving the object of “waste treats waste, waste to wealth.” For the said new technical solutions, two Chinese patent applications concerning processes and main apparatuses have been filed with the Chinese Patent Office respectively, with the patent application number 00119453.4 and 02203582.6. In addition, a Chinese application for patent for invention had also been filed, with the patent application number 01126707.0. The patent for utility model No. ZL02203582.6, with the title of “A Multiphase Reactor” had been granted. The patent ZL02203582.6 is mainly concerned about a cone-shaped build-in member, composed of a cone-shaped ring and a cone body, which is mounted inside the reactor. Owing to the said build-in member, the velocity and direction of the fluids inside the reactor are forced to change continuously, so as to strengthen the contact among gas, liquid and solid phases and to improve the reaction process. Meanwhile, the build-in member can retard the deposition of solid materials in the reactor. This kind of build-in member is simple in structure, and can prevent corrosion and abrasion readily. The conical surfaces of the cone body and conical ring housing of this conical build-in member are rotation surfaces formed by rotating straight lines, as a generatrix, round a rotation axis. However, these rotation surfaces can hardly fit for complicated practical situations. If the generatrix is changed from straight lines to a curved line as required, then the curved line is rotated round the rotation axis to form rotation surfaces, the axisymmetric body and annular axisymmetric body, which are formed by the above-mentioned rotation surfaces, replace the previous cone body and conical ring; the rotary build-in member, comprised of the axisymmetric body and the annular axisymmetric body, replace the previous conical build-in member. The rotary build-in member can effectively improve the flow pattern of the fluids and improve the contact among gas, liquid and solid phases of the reactants, and speed up the mass transfer Therefore, the multiphase reactor could fit with more situations, and could be employed in even more three-phase or two-phase reactions.